So is Old Magic part of the Hunter universe, or isn't it? The cover font is the same, but you say it's a different genre, and the cover imagery is definitely different, yet you also say it's firmly in your universe, so I'm confused. And if I'm confused about that, then I'm probably not the only one, which might be why sales underperformed your expectations.
The original idea was a standalone.
What happened was in Merlin, he vanished for a few seconds, which for him was a week.
So in Old Magic, he spends that week with the new MC. And later, several months. So Old Magic is for my Merlin character, a sequel to the last book, just told from the PoV of a new character.
It also references events a couple of years in the future already documented in a short story, which was made into a movie for a later book, and itself references in a number of other places.
The universe covers 4100 years, with the main prequel stuff happening in 1969 and 2022. This is 2019-2021 filling part of that timeline, from a new PoV.
I also bring back a character from the future, and that character takes back information my Merlin character is unable to give them himself, so it sets up part of what I need for the first book in the next series, Mage King.
It's also Earth, before it becomes uninhabitable. With the main character becoming aware of that, and it sets up a possible series, set with the events of the exodus of mankind to the stars as a it's focus. So if I want to, I can tell the story of how humans left Earth, from the perspective of someone operating behind the scenes to make it happen. That would be 100 odd years of story, and require a second MC to take over mid way through.
So what was originally a stand alone idea, when it came to be written, turned into just another universe story, set in a time which hadn't been used yet.
If I were in your shoes, I'd publish books in this genre under a different name (e.g. T. Ellis).
It's a thought for if I do write a non-universe standalone in the future.
Interestingly, this new MC provides me with a pen name for writing space detective if I move that way in the future.
